Being kind is the easiest thing someone can do. Literally all you have to do is be nice. Like just don't be mean. Seriously. I don't understand why there are mean people in the world still? Can anyone tell me they like people who are mean? No one likes someone who is mean to others or especially mean to them. Mean people suck, and you know you've seen that bumper sticker before.
Human beings aren't meant to be rude to one another. All people need to do is smile and be polite. Those two things alone can make a person's day. It can change someone's mood from angry to happy. Kindness comes from a deeper sense of caring about others. When you care about someone, you are naturally kind to them. When you are kind to someone, both people benefit by feeling happiness.
The more kind you are, the more kind others will be. It is like the ripple effect. When someone is nice to you, you feel the need to be nice to the next person you come into contact with. Then that person will be kind to the next person they interact with and so on. Kindness does not require a skill, it requires having a genuinely good heart. If you have a good heart, you should have no problem acting with kindness. If you find that being kind is annoying or difficult, then maybe you need to dig a little deeper into who you are or who you want to be. Just be kind to eachother you guys.